Field of the Invention
The present invention relates to a data transmission method for a mobile terminal, and more particularly, to a method and apparatus for a data transmission according to a battery use pattern.
Related Art
With the supply of mobile terminals such as smart phones over recent years, the energy consumption and low battery of mobile terminals becomes an important issue. According to this, a method of analyzing and utilizing a terminal energy use pattern of a user has been researched, such as transmitting data adaptively according to a delay-tolerance or scheduling tasks according to a power consumption. For example, by analyzing the energy use pattern of a smart phone of a user, the future energy remains are anticipated, and accordingly, the data of more delay-tolerance is transmitted or tasks are actively scheduled when there is spare energy. Otherwise, the data transmission or scheduling for the tasks is delayed as much as possible.
As one of the studies researched previous to the development of such algorithm, there is a study for a smart phone energy use pattern of a user [D. Ferreira, A. K. Dey and V. Kostakos, “Understanding Human-Smartphone Concerns: A Study of Battery Life,” Pervasive 2011, LNCS 6696, pp. 19-33, 2011]. In this study, a developed application is installed on 4000 or more android smart phones, and energy remains of the smart phones are measured.
In addition, in another study [E. Oliver, and S. Keshav, “An Empirical Approach to Smartphone Energy Level Prediction,” ACM UbiComp′ 11, Sep. 17-21, 2011, Beijing, China], after measuring energy use patterns for 20,100 smart phone users, a simple algorithm is proposed to anticipate future battery remains by classifying the users. The algorithm proposed by the study uses a method of anticipating the future battery remains using an average battery discharge rate and a charging time of a user. As a result of simulation, the algorithm shows an accuracy of about 72%. Although there are studies for analyzing smart phone energy use patterns of users, there was no study or invention for opportunistic transmission of delay-tolerant data by utilizing the studies.
Meanwhile, in an environment in which heterogeneous networks are coexist such as a cellular network and a wireless LAN (Wi-Fi), there is a study that proposes an algorithm for determining on which network is selected by collectively considering a power consumption of a terminal and a delay time, when the terminal performs a uplink or downlink transmission of delay-tolerant data [M. Ra, J. Peak, A. Sharma, R. Govindan, M. Krieger, and M. Neely, “Energy-delay tradeoffs in smart phone applications,” in Proc. of MobiSys, SF, Calif., USA, June 2010, pp. 255-270]. The study shows that the data transmission amount through the wireless LAN is three to four times greater than the data transmission amount through the cellular network in the case of consuming the same power amount. Meanwhile, in the algorithm, the fact that the wireless LAN may be usable intermittently only (e.g., in the case of meeting Wi-Fi access point) has been positively reflected.
According to this, since it is unable to use the wireless LAN in the case that the data delay time becomes elongated excessively, the data is transmitted through the cellular network in spite of consuming a lot of energy. Otherwise, in the case that there is the data delay time to spare, the data transmission is holding until it is available to access an energy efficient wireless LAN.
Although such a study proposes the algorithm of selecting an optimal network for transmitting data by considering energy efficiency so far as a delay of the data transmission is tolerant, the study did not consider current battery remains of a terminal. That is, in order to use the energy of terminal efficiently, the energy remains should be considered together with the delay-tolerance of data. That is, in the case that energy is in short, the data transmission should be able to be stopped even though the terminal meets an energy efficient wireless LAN.
However, studies and invention including the study above still do not consider the battery remains.